


Eternal Youth

by st_r_trk_fangasm



Category: Star Trek: Alternate Original Series (Movies)
Genre: De-Aged!Jim, Family, Gen, Hurt/Comfort, Mission Gone Wrong, baby care, enterprsie crew
Language: English
Status: In-Progress
Published: 2017-01-19
Updated: 2017-01-19
Packaged: 2018-09-18 12:11:38
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 4,360
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/9384503
Author URL: https://archiveofourown.org/users/st_r_trk_fangasm/pseuds/st_r_trk_fangasm
Summary: Another mission, another incident, but this time it's going to take a lot longer than a few hours to correct. Captain James T. Kirk has been turned into an infant by an alien spore and Spock, now temporarily in command of the USS Enterprise, must find a solution to return his friend to his just age or be forced to turn over everything to the federation.





	1. Care

**Author's Note:**

> First time posting. No idea what will come of this fic, but I started writing it just after reading a Star Trek novel and thought that this de-aged trope in the fanfiction universe always lacked a sci-fi feel. It's meant to be kind of funny, reading the crew caring for an infant, but there is more to it than that. So I hope this appeals to you as it does to me. Enjoy.

Spock was perfectly capable of taking care of the ship in the captain's stead. He was the first officer and commanding science officer of this vessel and he would not be 'put down', as the CMO had once said. It was taxing work and Spock could only keep at it, and have hope that no one called upon them for anything other than their current mission, at least until the captain's return to duty. A monotonous routine for the next few weeks was scheduled since their arrival to Elown, but they had extended it without the federation's permission. Spock, and the crew members involved, were all aware of the reasoning. That reasoning being; that their captain had been turned into a newborn infant while planet side. Such an occurrence happening was beyond comprehension, except that the culprit was a sentient plant and it's chemical make-up could scientifically prove to be, in fact, comprehensible. Eventually. 

"Eventually," Spock repeated to himself as he reviewed the research and reports. For that was what the Elownians told him when they'd asked for a solution. 

"He'll return to normal eventually. It's a blessing to be given youth again. Perhaps a little too much in this case, but youth all the same," one had said pleasantly. None of the Elownians were concerned by this in the least, but they were far from human beings, and they were much more likely to be immune to any of its negative effects. They had to send a team down to confirm that the child the crew had found, was indeed James T. Kirk, then send a shuttle down to get the infant too small and too frail to beam up. Of course, McCoy was the first to retrieve the child. Spock did not deny him that. Spock, who had been aboard the ship since their arrival, went down to the docking bay to receive them in turn. Despite all the reports he'd been given, he was still shocked when McCoy stepped out of the shuttle craft with a crying bundle of blankets. The doctor looked deeply concerned, and with good reason, in Spock's opinion. What he held in his arms was still a deep pink newborn child, and neither of them could understand it. If they agreed on anything, it was that this situation was terrifying.

Spock worked at his computer, reviewing the latest reports and requesting further investigation on some details. Thus far, their findings did not solve reversing the effects and to Spock, this was key. They were 5 days and 3 hours into this mission and they had yet to give a full report in to the federation. A briefing had concurred that the crew's finding were too supernatural to report in. And if the federation took it seriously enough, their finding 'eternal youth' with living proof of its effects, was too good to keep the federation from taking over to turn in a profit. The federation may have a high ethical code of conduct, but if something of this calibre of interest was being placed in the palm of their hand, Spock could not see why they wouldn't. To make matters worse, should they take action, they would likely take their captain away and use him, whether humanly or not, as an experiment. The crew was taking care of their young captain, but understandably, he was still being used to experiment on. The infant was not… happy.

The door chimed and the good doctor let himself in with the child in his arms. Things were settling into a routine with the babe now, and that included the doctor visiting him in his quarters, but this was the first time he'd brought the infant.

"Good evening Captain Spock," he sang, bouncing in with the disgruntled gurgling babe.

"Doctor," Spock greeted, dismissing the man's disregard for etiquette. He glanced at Jim and saw he was aggressively biting on a rubber toy. Spock came to the conclusion before the doctor said.

"He's teething. Yeah." he said sympathetically. "Poor kid's just miserable." McCoy rocked the child who continued to drool and bite, then make gurgling noises.

"I understand that an infant's teething phase can be discomforting, doctor, but more importantly, this shows a great deal of aging that, as the research team has calculated and noted, is fluctuating. This poses somewhat of unknown on their research, especially when comparing it to the Elownians' data banks."

"Yeah I know. It's gonna take a lot longer than a few days to see how and when lil Jimmy is gonna be himself again." He looked down at 'lil Jimmy'. McCoy's face softened, frowning as he spoke in a whisper. "If he does anyway…"

"Doctor?"

"Well, yeah know, what if the stuff has a rebuff on him and it makes him age twice as fast and it just doesn't stop?" The doctor seemed to coddle the infant closer now. Spock refrained from mentioning, that factually, Jim was growing approximately a month per day within a margin of error for the fluctuating statistics. Truthfully, Spock disliked the doctor's very possible theory just as much as he did.

"I assure you that no one wishes ill of the captain and his safety is our first priority," Spock said, readying himself for the man's emotional response, but no argument came. Instead, Leonard displayed what Spock could understand as a paternal instinct. The doctor leaned in close and nuzzled the golden lock of hair on the infants forehead. Jim's eye closed, then opened wide to fix the doctor with, what the crew was referring to as, 'his big baby blues'. Spock was fascinated to be sure. The aesthetic appeal of those eyes on an infant were very powerful. The babe squirmed and giggled as McCoy continued to coo and nuzzle his face. Jim continued to laugh and the sound was stimulating. Spock was affected. A small smile creeped to the corner of his lips before he could repress it.

McCoy withdrew and reintroduced the teething ring. Jim took to it right away, continuing to rub his gums on the toy. It had been only 32 hours ago when Jim had been brought onto the bridge in a blanket, finally released from quarantine and looking at everything with large blue eyes while sucking on a pacifier. The bridge crew had their first look at the child then since he'd been brought aboard. Spock was relieved to have Mr. Scott take the child in his arms with joy. The engineer lifted the crew's spirits by accepting Jim's 'condition' and making light of it. They all knew it was far from a minor problem, but Spock knew that Jim would value keeping up the crew's moral.

"Well, let's make him happy and comfortable," McCoy sighed, breaking Spock's train of thought. The doctor went over to Spock's bed and set Jim down in the middle, but on the horizontal. Without regard to Spock's wishes, he took apart the bedding to create a barrier for the child, should he move too much and roll off the low bed.

"Doctor?" Spock began, as a mean to understand his current actions.

"Mama's going out for a drink tonight, Jimmy," he said to the child. "Spock'll keep you until morning. Nice, safe, logical vulcan. Your favourite," he grinned. Jim kicked his feet in the air, fidgeting. "Oh! Is it too warm in here?"

"Doctor, you do not understand. I am much too busy to care for him at the moment." 

"Ah keep your pants on! He's gonna fall right to sleep. And knowing you, you'll just meditate for a few hours tonight rather than sleep." he turned away, adjusting the thermostat to normal ship's temperature. Spock felt the change and frowned.

"You leave me little choice," Spock muttered as McCoy put the baby's blanket around the child in a bundle.

"He won't be any trouble. Besides, I thought you'd want a little practice considering you were going to raise your own a few months ago." Spock's jaw tightened.

"That is out of context. Jim is not my child and this is not a matter I wish to discuss," he said, meeting McCoy's gaze as he approached.

"Listen I'd love to talk more about it, but I've got a date with two shots and a blonde. Have a good night. Comm. me if you're worried-" he said as he left, his voice being cut off by the door closing. Spock wished to say that he does not worry, but one glance at the child dozing off on his covers made him uncertain.


	2. Attachment

**Summary for the Chapter:**

> Spock takes care of Jim.

Spock focused on his readings and found it very difficult to omit details for the reports in which he would have to send to the federation. He could not lie, especially when reporting such a finding, but he'd learned over the years to omit and suggest when reporting in. He'd learned much since causing Jim to lose his ship approximately 4 and a half years ago. But this was different, very different. Something like eternal youth could incite too much attention, and reporting an incapacitated captain for an uncertain amount of time was risky. No, Spock would not be the cause for the ship to be docked again.

He glanced again to the sleeping infant, wondering not for the first time, if this was truly thier captain and not some sort of cloned alien being. He'd sorted that doubt already though, the Elownians were honest and the data they'd given him was conclusive.

Spock could hear his little breaths clearly from where he was. The child squirmed uncomfortably again, but made no further signs of distress. He considered how they were caring for the infant, and was reminded of something his mother once said to him; it takes a village to raise a child. It was a human term that she'd used when his half brother, Sybok, would act out and would cause the neighbouring vulcans to help him learn control in their own ways. It would seem the crew was the village in this case. Everyone wanted to care for Jim; his physical being was dependent of this care. And he was growing rapidly. But what if, once his brain was developed enough for speech and cognitive thought, he would regain his memories?

Spock sat straighter than he already was.

What if, instead, Jim would actually have to relearn everything and his brain was actually wiped clean of everything he'd ever learned or experienced.

Spock took in a breath and let it out calmly. He needed to meditate; his mind was a mess of stray thoughts. So he rose from his seat and set up his meditation mat. He was about to light the incense, but he thought better of it. What if it bothered the child? Should Jim be irritated by it in some way, there would be a delay before the room could be filtered of its scent.

Spock sat on his mat and took his first breath, listening to the quiet hum of the ship, and the child's breath. He breathed out, then in, quieting his thoughts, and focusing on his most prominent concern. Jim.

Would Jim truly ever be Jim again? Had they already lost their captain in such a meaningless way? He'd died before, to save the crew, but had been revived by Khan's blood. Perhaps Khan's genetics still had some effects on Jim's being. Yet, there have never been any medical anomalies to suspect so. Jim was often allergic to things, but otherwise, quite healthy. Jim's list of allergies could not be dismissed from this situation of course, as it could still affect results. His immune system could be causing… or have already caused the spores to act differently upon him. Comparing the human to an Elownian, however, complicated things in this matter. Elownian were quadrupeds that were covered in thick ropes of hair, weighing approximately 5 000 pounds, a retractable head, and hid long appendages beneath the hair to reach and hold objects. They were a pleasant species, quite intelligent, but none of the crew cared for their oder. Such is why, Spock hypothesized, Jim withdrew from the area to the wilderness. Jim had an affinity for flowers. Not in a scientific way, as Spock had once assumed, but in an aesthetic way.

"I just think they're beautiful," Jim had said, taking in a deep breath of fresh air. "And they smell nice,"  
Spock recalled their exploratory mission on a primitive planet, Jim smiling in the sunlight, holding a bouquet to bring back to the ship.

A wail broke Spock's concentration. Jim was crying and kicking the blanket away from himself. Spock rose and looked over the child. With his mouth open, he could see the very edge of some teeth coming in, but currently, he was more concerned with trying to sooth the small being. Jim's face was turning a blotchy red with his efforts and Spock was at a loss. He had yet to hold or even touch Jim since the incident, and now he did not know if he should. Jim's screaming quieted a moment, his face contorting, then relaxing. Then an unpleasant squishy sound, followed by popping made the child seem content for a moment. The vulcan grimaced and picked up his communicator.

"Dr.McCoy," Spock called but was put to voicemail. Spock could only assume that the off duty doctor was away from his communicator for the moment. He did not wish to make an announcement, thus he pressed the communication button on his desk. "Spock to Med Bay,"

"Med Bay, this is nurse Chapel. What can I do for you Captain?" the woman replied. Spock felt uncomfortable being called "Captain" unless they were on duty, but said nothing as the nurse was currently working the shift.

"Doctor McCoy has left… 'the infant' in my care without proper equipment and instructions. Please send someone to my quarters," he said. He heard the nurse chuckle on the other end of the communications to which he raised a brow.

"Does our little captain need a diaper change?" she teased. Spock still could not fully understand why humans found it humorous that some knew not how to care for children. It was a serious problem to be inept in child care and should not be taken lightly.

"Accurately stated, nurse Chapel. Have the child's care bag and able personnel here in 5 minutes, Spock out," he closed the communication and returned to see the child continuing to wiggle and make strange faces. In a study, it was fascinating to see a being learning how to control his body and trying to understand what everything is for. In the current situation, however, Spock could not appreciate it. His captain has been de-aged to a helpless infant by an unknown spore from a sentient plant with no known language, and all the research and time it would take to, if possible, reverse this, was also unknown.

He needed to meditate.

Spock watched helplessly from behind the grill as Jim began making uglier grimaces, most likely about to cry out for someone to change him. As predicted, 47 seconds later, Jim began to cry and Spock could not simply stand watch. He approached the child and knelt by the bed.

"Jim," he began, trying for the first time to address him directly as other crew members have. Jim wasn't listening though, continuing to cry and kick his feet. His little fists flailed aimlessly in the air. Spock knew that he should probably pick him up or… something which involved physical contact, but he couldn't bring himself to do it. 

He decided to meditate on that later too.

The door chimed and Spock rose to his feet before allowing entry. He expected Nurse Chapel or perhaps another nurse on duty, but it was McCoy who entered.

"Eh, sorry Spock, I forgot to leave ya the bloody bag-" he stopped as he looked down at the child still crying on the bed. "Are you serious? You didn't even bother to pick up the poor kid?" How the doctor came to such a conclusion, Spock was uncertain, but as he was not incorrect, he said nothing.

"Come 'ere sport," he said to Jim, picking him up and making hushing noises. "You could at least make an effort Spock," he muttered in his direction as he took over the desk space to change the child.

"You had the supplies," Spock reminded. The door chimed again and Spock allowed entry, assuming it was the nurse he'd sent for. He was correct this time, an ensign came with a small bag on his side.

"Pardons, Mr. Spock, we couldn't find- Oh! The bag…" he saw McCoy with it and sighed in relief. "Doctor McCoy, we believed you off-"

"Yeah I was, but never mind that. Did Spock call for you to come change this poor kid?" the doctor was pulling out the new diaper and wipes from the bag. The ensign glanced quickly over to Spock and back to McCoy before nodding once. "Thank-you Ensign Reban, please keep that bag in the med bay for emergency use. I've got it from here,"

"Yes Sir," he nodded. "Good night Captain," he looked at Spock, then down at Jim who continued to cry. He gave a curt bow. "Captain," he said softly before taking his leave.

"Now Mister Spock, you're about to learn how to change a diaper," McCoy informed him, motioning for him to step closer. Spock did no such thing.

"I would rather not-"

"Just watch me do it you big baby!" Leonard scoffed, then continued muttering to himself. Spock could hear every word.

"I was never schooled in child care, nor was that ever covered in Starfleet Academy. Furthermore-"

"You big eared hobgoblin! Just watch what I do." he ordered, setting up the desk with things and removing the little one piece pajama that Jim wore. "Now make sure you have everything ready on the side because once he's got that diaper off, he might just start whizzing all over you the moment you look for something in the bag."

"Whizzing?" Spock's brow rose.

"Peeing Spock. Peeing," he filled in. "They do that."

Spock stayed silent, letting the doctor continue his lesson.

"Now un-stick these things and pull down the top, ever so carefully," he began. As he did so, sure enough, Jim was 'whizzing'. McCoy put the flap back down. "Ha! Thought you could get Uncle Bones did ya!" he chuckled as Jim bit at his knuckles innocently. The doctor turned to Spock for a moment then back again, losing the grin. "So let him finish, then when you know he's done, pull away the flap and lift his ankles in one hand to raise his bottom away from the mess." He demonstrated as much. "Use the cleanest parts you can for the excess stuck to him, then toss it. Get those wipes, clean him up, then powder him down." Jim kicked the powder bottle off the desk before Leonard could think better of it. "And typically keep things away from kicking range…"

"Indeed," Spock leered at the mess all over the floor now before picking up the bottle and slipping it back in the bag.

"Sorry 'bout that. I haven't changed diapers since Joanna was born. 'course, she was an angel compared to you," McCoy turned his frown to a soft smile when addressing Jim. "Ah, look at you, so cute," he commented, petting the child's belly now that he wasn't using that hand to hold him in place. "Bet you're gonna be the definition of terrible twos,"

Spock watched on silently as McCoy forgot himself and started playing with the infant. Holding his small hands with one finger and waggling it. He continued to make cooing noises and tell him how cute he was. Spock could see it in the doctor's slouch that his drinks had inebriated him and was at the point of fatigue. Spock made a small noise to remind the doctor of his presence. McCoy blinked a few times to gather himself before clearing his throat and putting on the new diaper. He put the pajama back on, snapping it all back into place.

"And there ya go! Clean baby Jimmy!" he clapped before scooping up the child in his arms. "Now Spock I need you to give him his bottle, burp him, and put him to bed. He'll go right to sleep, I promise," McCoy stated, outstretching Jim towards Spock, but the vulcan was unwilling, thus Jim nearly took a dive. A 'heart-stopping' moment to be sure. "Spock! What's wrong with you? Hold him for a second!" Jim was crying loudly now. "Now look what you've done!"

"I would rather- I would rather not…" Was Spock's response. His chest was still tight from the moment Jim fell a few inches between them, and he knew it was illogical to hesitate, yet he could not come to terms with himself to simply hold this child. McCoy stared down hard at him.

"You know," he began, holding Jim close and bouncing him a little to sooth the crying infant. "I understand if you'd like to pretend this isn't happening, but it is. This is Jim and we have to take care of him! He may not even have long to live and you better be ready and willing to give your closest friend the happiest days of his life!"

"I-" Spock had prepared to argue, but found that to be the answer he'd been searching for. To touch Jim, to hold him like this; it would indeed give way to accepting the situation as truth. An illogical fear of the truth and what could yet be the truth.  
Spock inhaled and let it out softly.

"You are correct," he began. "I do not want to accept this. I want to find a solution and return him to his original form. There is no alternative." McCoy opened his mouth, but Spock continued. "But I realize that I cannot ignore what is happening now. Yes, what ifs, and theories, these do not change. What is happening right now though, it may be just as important,"

They stood quietly until Spock put out his hands and McCoy came foreword. He gently handed him the babe, Spock imitating the doctor's manner of holding the head and the back.

"That's right, hold his head and support his back. Pull him close to your chest." McCoy instructed softly. Spock did so, adjusting the child moving about. He thought about how his father must have felt, holding him as a newborn, so small and frail… and human. "He just wants to feel safe." McCoy said before he moved away, going to get the bottle of formula and a cloth. Spock composed himself, looking down at the child who continued to drool and squirm. He was barely larger than his hand when they'd brought him up from the planet, and now he was approximately twice that size. Spock was fascinated by how strong Jim felt. The child was a soft cushion of skin with strong muscles beneath.

McCoy came back and showed him how to check the temperature before feeding. Then he demonstrated the angle in which to feed him. Spock adhered to his advice and watched the child bite at the tip before catching on that food was coming from it. Once the suckling began, Jim was solely focused on this task. He drank greedily.

"Don't let him drink too fast," McCoy warned, crossing his arms over his chest as he looked on. Spock pulled the bottle away somewhat, letting the child remember to breathe. Jim complained, but he was still being fed, thus he did not fuss too much. 

"Fascinating," Spock said aloud. He felt protectiveness rising in himself. He did not know how he could care for Jim like this, but he would make the attempt. The beautiful baby in his arms was his to protect. 

Then he realized that this was what his mind had feared. He feared growing attached to the child and that in doing so, he would accept Jim in this form; that it was all true.

He looked at McCoy and understood that this was the doctor's doing. He knew Spock was repressing his emotions in order to keep up with running the ship. To not have Jim in command, to instead have a defenseless infant to care for, to know that his best friend was being poked and prodded beyond his understanding… Spock was not unaffected.

He accepted this now. And he made a promise to himself, that he would not abandon or deny Jim anything. He would be safe with him. He would protect him.

Jim's little hand touched his pinky and Spock's mind felt it before his skin did. The link that he and Jim shared opened up like a warm ray of sunshine hitting his face. This was Jim, and the relief he felt weakened his knees.

"Spock?" McCoy began, "You okay?"

"It is Jim," he confirmed aloud as he withdrew the empty bottle from him, breaking their connection.

"Yeah?" the doctor said patiently. "What about him?"

"I… " he continued his phrase in vulcan, to which the doctor's translator simplified as "I see him". The doctor's brow raised, but seemed to dismiss the comment. Spock did not expect him to understand.

"Alright, but you're gonna have to burp him soon," he reminded, putting the long cloth on Spock's shoulder. Spock continued to stare down at the child until Jim yawned. He then shifted him up and leaned him on his shoulder. 

'So small', he thought to himself, rubbing the child's clothed back. He gave gentle taps to his back as McCoy instructed, getting a few burps from the little boy without causing him to puke anything. McCoy seemed satisfied by that in any case, taking his leave to 'catch a few Zs'. Spock was to put Jim down to sleep, but instead continued to hold him in one arm as he worked.

It was as he had feared, but with their link alive and well, he felt assured that this attachment was justified.

**Notes for the Chapter:**

> Hope this is as sweet to you as it is to me. I'm sorry my writing is chaotic mess most of the time. I'm trying XD

**Author's Note:**

> Well that's the first part I had started on. The chapters will probably get longer as I go. I would like to go through just about every phase of a child's life cycle and have fun with that.
> 
> Hey, if you guys have any good de-aged fics, please send them my way!


End file.
